JP6623329B2

JP6623329B2 - Corrosion sensor

Info

Publication number: JP6623329B2
Application number: JP2015132596A
Authority: JP
Inventors: 修二石原; 重信貝沼
Original assignee: Kyushu University NUC; Mitsui E&S Machinery Co Ltd
Current assignee: Kyushu University NUC; Mitsui E&S Machinery Co Ltd
Priority date: 2015-07-01
Filing date: 2015-07-01
Publication date: 2019-12-25
Anticipated expiration: 2035-07-01
Also published as: JP2017015560A

Description

この発明は、腐食センサに係り、特に、所定の方向における腐食環境の変化を評価する腐食センサに関する。 The present invention relates to a corrosion sensor, and more particularly, to a corrosion sensor for evaluating a change in a corrosion environment in a predetermined direction.

橋梁、街灯、標識等、自然環境に晒される鋼構造物は、長期間にわたる耐久性を維持させるために、腐食状況を評価する必要がある。特に、点検が困難な腐食として、例えば、外観から確認し難い構造物の基部、すなわち、大気と地中との境界付近で発生する地際腐食が知られている。これは、腐食環境性が大気中と地中においてそれぞれ異なるため、大気中から地中に至る構造物に地際を隔てて電位差が生じ、さらに雨水などの水分がその地際部分に滞留することで構造物の地際部分が電気的に短絡されてマクロセル腐食電流が発生し、電池作用により構造物の地際部分が腐食されるものである。このような、外観からの確認が困難な箇所で発生する腐食に対応するために、構造物周辺の腐食環境性を測定することが求められている。 Steel structures exposed to the natural environment, such as bridges, street lights, signs, etc., need to be evaluated for their corrosion status in order to maintain long-term durability. In particular, as corrosion that is difficult to check, for example, ground corrosion that occurs near the base of a structure that is difficult to confirm from the appearance, that is, near the boundary between the atmosphere and the ground is known. This is because the corrosiveness of the environment differs between the atmosphere and the ground, causing a potential difference across the ground between structures from the air to the ground, and furthermore, moisture such as rainwater stays at the ground. In this case, the ground portion of the structure is electrically short-circuited to generate a macrocell corrosion current, and the ground portion of the structure is corroded by the battery action. In order to cope with such corrosion that occurs in places where it is difficult to confirm the appearance, it is required to measure the corrosive environmental properties around the structure.

そこで、例えば、特許文献１には、土壌中の金属構造物の埋設位置近傍に土壌表面部から金属試験体を挿入することにより土壌中の金属構造物の腐食を評価する方法が開示されている。土壌中に挿入されている金属試験体に生じるマクロセル腐食電流を測定することで、土壌中の金属構造物の腐食の進行が評価され、挿入から所定期間後に引き抜いて金属試験体の腐食減肉を測定することで、土壌中の深さ方向に沿った金属構造物の腐食状況の変化が評価される。 Therefore, for example, Patent Literature 1 discloses a method for evaluating the corrosion of a metal structure in soil by inserting a metal specimen from the surface of the soil near the buried position of the metal structure in soil. . By measuring the macrocell corrosion current generated in the metal specimen inserted in the soil, the progress of corrosion of the metal structure in the soil is evaluated, and after a predetermined period from the insertion, the metal specimen is pulled out to reduce the corrosion thinning of the metal specimen. By measuring, the change in the corrosion state of the metal structure along the depth direction in the soil is evaluated.

特開２００８−２９８６８８号公報JP 2008-298688 A

しかしながら、構造物の腐食は、その周辺に存在する酸素濃度、水素イオン指数（ｐＨ）、温度および湿度などの腐食環境性の違いに応じて局所的に進行するため、特許文献１に開示された方法のように、土壌中の金属構造物の埋設位置の近傍に金属試験体を挿入しても、評価対象となる金属構造物を直接測定するわけではなく、金属構造物の腐食状況、特に、所定の方向における腐食環境の変化を正確に評価することができないという問題がある。 However, since the corrosion of the structure locally progresses in accordance with the difference in the corrosive environment such as the oxygen concentration, hydrogen ion exponent (pH), temperature, and humidity existing around the structure, it is disclosed in Patent Document 1. Even if a metal specimen is inserted near the buried position of the metal structure in the soil as in the method, the metal structure to be evaluated is not directly measured, but the corrosion state of the metal structure, particularly, There is a problem that a change in the corrosive environment in a predetermined direction cannot be accurately evaluated.

この発明は、このような従来の問題点を解消するためになされたもので、構造物の所定の方向における腐食環境の変化を正確に評価することができる腐食センサを提供することを目的とする。 The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a corrosion sensor capable of accurately evaluating a change in a corrosion environment in a predetermined direction of a structure. .

この発明に係る腐食センサは、計測対象となる構造物の表面上に配置され且つ表面および裏面を有する平板形状の基板と、基板の表面上で且つ所定の方向に配列された複数の試料極と、基板の表面上に配置され且つ所定の方向における複数の試料極の配置位置を含むように複数の試料極に並んで所定の方向に延びる共通の対極と、複数の試料極および共通の対極に接続され且つ複数の試料極をそれぞれ共通の対極に接続することにより形成される複数の腐食回路を流れる複数の腐食電流に基づいて所定の方向における腐食速度の分布を計測する計測部とを備え、複数の試料極および共通の対極は、基板の表面において同一面上に並んで配置されているものである。
The corrosion sensor according to the present invention includes a plate-shaped substrate disposed on the surface of a structure to be measured and having a front surface and a back surface, and a plurality of sample electrodes arranged on the surface of the substrate and arranged in a predetermined direction. A common counter electrode that is arranged on the surface of the substrate and extends in a predetermined direction along with the plurality of sample electrodes so as to include the arrangement position of the plurality of sample electrodes in the predetermined direction; and a plurality of sample electrodes and a common counter electrode. A measuring unit that measures a corrosion rate distribution in a predetermined direction based on a plurality of corrosion currents flowing through a plurality of corrosion circuits formed by connecting and connecting a plurality of sample electrodes to a common counter electrode, respectively . The plurality of sample electrodes and the common counter electrode are arranged side by side on the same surface on the surface of the substrate .

共通の対極は、複数の試料極と同一の材料からなっていてもよい。特に、複数の試料極と共通の対極は、鉄めっきから形成することができる。あるいは、共通の対極は、複数の試料極と同一の材料を主成分とし且つ複数の試料極より貴である材料からなることが好ましい。
基板の裏面が熱伝導シートを介して構造物の表面上に貼り付けられることが好ましい。
計測部は、複数の試料極のそれぞれに対して、試料極を共通の対極に接続することにより形成される腐食回路を流れる腐食電流を時間積分することにより試料極における腐食速度を計測することが好ましい。 The common counter electrode may be made of the same material as the plurality of sample electrodes. In particular, the common counter electrode with the plurality of sample electrodes can be formed from iron plating. Alternatively, it is preferable that the common counter electrode is made of a material whose main component is the same material as the plurality of sample electrodes and which is more noble than the plurality of sample electrodes.
It is preferable that the back surface of the substrate is stuck on the surface of the structure via the heat conductive sheet.
The measurement unit measures the corrosion rate at the sample electrode by integrating the corrosion current flowing through the corrosion circuit formed by connecting the sample electrode to the common counter electrode with respect to each of the plurality of sample electrodes. preferable.

この発明によれば、計測対象となる構造物の表面上に配置される基板と、基板の表面上で且つ所定の方向に配列された複数の試料極と、基板の表面上に配置され且つ所定の方向における複数の試料極の配置位置を含むように複数の試料極に並んで所定の方向に延びる共通の対極とを備え、計測部が、複数の試料極をそれぞれ共通の対極に接続することにより形成される複数の腐食回路を流れる複数の腐食電流に基づいて所定の方向における腐食速度の分布を計測するので、構造物の所定の方向における腐食環境の変化を正確に評価することが可能となる。 According to the present invention, a substrate arranged on the surface of a structure to be measured, a plurality of sample electrodes arranged on the surface of the substrate and in a predetermined direction, and a predetermined electrode arranged on the surface of the substrate and A common counter electrode extending in a predetermined direction in parallel with the plurality of sample electrodes so as to include the arrangement positions of the plurality of sample electrodes in the direction of, and the measurement unit connects each of the plurality of sample electrodes to the common counter electrode. Since the distribution of corrosion rate in a predetermined direction is measured based on a plurality of corrosion currents flowing through a plurality of corrosion circuits formed by the method, it is possible to accurately evaluate a change in a corrosion environment of a structure in a predetermined direction. Become.

この発明の実施の形態に係る腐食センサの構成を示す平面図である。It is a top view showing the composition of the corrosion sensor concerning an embodiment of this invention. 腐食センサの電極部を示す平面図である。It is a top view which shows the electrode part of a corrosion sensor. 複数の試料極における電極部の部分断面図である。It is a partial sectional view of the electrode part in a plurality of sample electrodes. 共通の対極における電極部の部分断面図である。It is a partial sectional view of an electrode part in a common counter electrode. 構造物の表面上に設置された電極部を示す部分断面図である。It is a fragmentary sectional view showing the electrode part set up on the surface of the structure. 試料極と共通の対極が水中に没した状態を示す断面図である。It is sectional drawing which shows the state where the counter electrode common to a sample electrode was immersed in water. 実施例１における測定結果を示すグラフである。5 is a graph showing measurement results in Example 1. 実施例２における測定結果を示すグラフである。9 is a graph showing measurement results in Example 2.

以下、この発明の実施の形態を添付図面に基づいて説明する。
図１に実施の形態に係る腐食センサの構成を示す。この腐食センサは、電極部１と、ケーブル２を介して電極部１に接続された計測部３を有している。
電極部１は、腐食環境の評価対象となる構造物の表面上に設置されるもので、平板形状の基板４を有し、基板４の表面４Ａ上に複数の試料極５が形成されると共に複数の試料極５の近傍に共通の対極６が形成されている。
複数の試料極５は、所定の方向Ｄに１列に配列されており、共通の対極６は、所定の方向Ｄにおける複数の試料極５の配置位置をすべて含むように複数の試料極５に並んで所定の方向Ｄに延びている。 Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 shows a configuration of the corrosion sensor according to the embodiment. This corrosion sensor has an electrode unit 1 and a measuring unit 3 connected to the electrode unit 1 via a cable 2.
The electrode unit 1 is provided on the surface of a structure to be evaluated for a corrosive environment, has a flat substrate 4, and has a plurality of sample electrodes 5 formed on a surface 4 </ b> A of the substrate 4. A common counter electrode 6 is formed near the plurality of sample electrodes 5.
The plurality of sample electrodes 5 are arranged in a row in a predetermined direction D, and the common counter electrode 6 is arranged on the plurality of sample electrodes 5 so as to include all the arrangement positions of the plurality of sample electrodes 5 in the predetermined direction D. They extend in a predetermined direction D side by side.

図２に示されるように、基板４の表面４Ａ上で且つ基板４の端部には、複数の試料極５に対応する複数の第１の端子７が配列形成されており、互いに対応する試料極５と第１の端子７が基板４の表面４Ａ上に形成された配線８を介して電気的に接続されている。
同様に、基板４の表面４Ａ上で且つ基板４の端部には、複数の第１の端子７に隣接して１つの第２の端子９が形成され、共通の対極６と第２の端子９が基板４の表面４Ａ上に形成された配線１０を介して電気的に接続されている。
図１に示した計測部３は、複数の第１の端子７を介して複数の試料極５に接続されると共に、第２の端子９を介して共通の対極６に接続されている。 As shown in FIG. 2, a plurality of first terminals 7 corresponding to a plurality of sample electrodes 5 are arranged and formed on the surface 4A of the substrate 4 and at the end of the substrate 4. The pole 5 and the first terminal 7 are electrically connected via a wiring 8 formed on the surface 4A of the substrate 4.
Similarly, one second terminal 9 is formed on the surface 4A of the substrate 4 and at the end of the substrate 4 adjacent to the plurality of first terminals 7, and the common counter electrode 6 and the second terminal 9 is electrically connected via a wiring 10 formed on the surface 4A of the substrate 4.
The measuring unit 3 shown in FIG. 1 is connected to a plurality of sample electrodes 5 via a plurality of first terminals 7 and to a common counter electrode 6 via a second terminal 9.

基板４は、例えば、ガラスエポキシ樹脂等の絶縁性樹脂から形成されており、図３および図４に示されるように、基板４の表面４Ａ上に複数の試料極５および共通の対極６が直接配置されている。
試料極５は、評価対象となる構造物を構成する材料と同一組成の材料から形成されることが好ましく、鋼構造物の腐食環境の変化を評価する場合には、例えば、鉄めっきを形成材料として使用することができる。
また、共通の対極６は、試料極５と同一組成の材料から形成することができ、試料極５を鉄めっきから形成する場合には、共通の対極６も鉄めっきから形成することができる。 The substrate 4 is formed of, for example, an insulating resin such as a glass epoxy resin. As shown in FIGS. 3 and 4, a plurality of sample electrodes 5 and a common counter electrode 6 are directly formed on a surface 4A of the substrate 4. Are located.
The sample electrode 5 is preferably formed of a material having the same composition as the material constituting the structure to be evaluated. When evaluating a change in the corrosive environment of the steel structure, for example, an iron plating material is used. Can be used as
In addition, the common counter electrode 6 can be formed from a material having the same composition as the sample electrode 5, and when the sample electrode 5 is formed from iron plating, the common counter electrode 6 can also be formed from iron plating.

複数の試料極５および共通の対極６は、各種の薄膜形成方法を使用して、複数の第１の端子７、複数の配線８、第２の端子９および配線１０と共に同一工程で基板４の表面４Ａ上に成膜し形成することができる。
なお、複数の試料極５、共通の対極６、複数の第１の端子７、第２の端子９、配線８および１０は、いずれも基板４の表面４Ａ上に配置されており、図３および図４に示されるように、基板４の裏面４Ｂ側には、電極、端子、配線等の部品が一切配置されていない。 The plurality of sample electrodes 5 and the common counter electrode 6 are formed together with the plurality of first terminals 7, the plurality of wirings 8, the second terminals 9, and the wirings 10 on the substrate 4 in the same process using various thin film forming methods. It can be formed by forming a film on the surface 4A.
Note that the plurality of sample electrodes 5, the common counter electrode 6, the plurality of first terminals 7, the second terminals 9, and the wirings 8 and 10 are all disposed on the surface 4A of the substrate 4; As shown in FIG. 4, no components such as electrodes, terminals, and wiring are arranged on the back surface 4B side of the substrate 4.

計測部３は、ケーブル２を介して接続された電極部１の複数の試料極５をそれぞれ共通の対極６に接続することにより形成される複数の腐食回路を流れる複数の腐食電流Ｉｃを測定する。具体的には、計測部３は、複数の試料極５のうちの１つの試料極５を共通の対極６に接続することで形成される１つの腐食回路を流れる腐食電流Ｉｃを測定した後、この試料極５を共通の対極６から遮断し、次の試料極５を共通の対極６に接続することで形成される次の腐食回路を流れる腐食電流Ｉｃを測定する。このようにして、複数の試料極５が順次共通の対極６に接続され、それぞれ形成された腐食回路を流れる腐食電流Ｉｃが測定される。
計測部３は、さらに、複数の腐食回路を流れる複数の腐食電流Ｉｃをそれぞれ時間積分することにより、複数の試料極５における腐食速度をそれぞれ算出し、これらの腐食速度に基づいて所定の方向Ｄにおける腐食速度の分布を計測する。 The measuring unit 3 measures a plurality of corrosion currents Ic flowing through a plurality of corrosion circuits formed by connecting the plurality of sample electrodes 5 of the electrode unit 1 connected via the cable 2 to the common counter electrode 6, respectively. . Specifically, the measuring unit 3 measures the corrosion current Ic flowing through one corrosion circuit formed by connecting one sample electrode 5 of the plurality of sample electrodes 5 to the common counter electrode 6, and then measures The sample electrode 5 is cut off from the common counter electrode 6, and the corrosion current Ic flowing through the next corrosion circuit formed by connecting the next sample electrode 5 to the common counter electrode 6 is measured. In this manner, the plurality of sample electrodes 5 are sequentially connected to the common counter electrode 6, and the corrosion current Ic flowing through each formed corrosion circuit is measured.
The measuring unit 3 further calculates the corrosion rates at the plurality of sample electrodes 5 by time-integrating the plurality of corrosion currents Ic flowing through the plurality of corrosion circuits, respectively, and determines a predetermined direction D based on the corrosion rates. The distribution of the corrosion rate at is measured.

次に、実施の形態に係る腐食センサの作用について説明する。
まず、図５に示されるように、腐食環境の変化を評価しようとする構造物１１に電極部１が設置される。このとき、熱伝導シート１２を介して基板４の裏面４Ｂを構造物１１の表面上に貼り付けることにより、電極部１の設置が行われる。
熱伝導シート１２としては、両面に粘着材が付着された市販の熱伝導シートを使用することができる。熱伝導シートに付着されている粘着材を利用して、基板４の裏面４Ｂを構造物１１の表面上に貼り付けることが可能となる。 Next, the operation of the corrosion sensor according to the embodiment will be described.
First, as shown in FIG. 5, the electrode unit 1 is installed on a structure 11 in which a change in a corrosive environment is to be evaluated. At this time, the electrode unit 1 is installed by attaching the back surface 4B of the substrate 4 to the surface of the structure 11 via the heat conductive sheet 12.
As the heat conductive sheet 12, a commercially available heat conductive sheet having an adhesive material attached to both surfaces can be used. The back surface 4B of the substrate 4 can be stuck on the surface of the structure 11 using the adhesive attached to the heat conductive sheet.

なお、電極部１は、複数の試料極５の配列方向である所定の方向Ｄが、腐食環境の変化を評価しようとする方向と一致するような向きで構造物１１の表面上に設置されているものとする。
例えば、水上から水中にまで至る構造物１１に対して水面の上下における腐食環境の変化を評価しようとする場合には、所定の方向Ｄを鉛直方向に向けて電極部１が設置される。
ここで、共通の対極６は、所定の方向Ｄにおける複数の試料極５の配置位置をすべて含むように所定の方向Ｄに延びているので、複数の試料極５のうち最も下方に位置する試料極５が水中に没したときには、この試料極５の配置位置に対応する部分の共通の対極６も水中に没することとなる。 The electrode unit 1 is installed on the surface of the structure 11 such that a predetermined direction D, which is an arrangement direction of the plurality of sample electrodes 5, matches a direction in which a change in the corrosive environment is to be evaluated. It is assumed that
For example, when it is intended to evaluate a change in the corrosive environment above and below the water surface for the structure 11 extending from the water surface to the underwater surface, the electrode unit 1 is installed with the predetermined direction D directed vertically.
Here, since the common counter electrode 6 extends in the predetermined direction D so as to include all of the arrangement positions of the plurality of sample electrodes 5 in the predetermined direction D, the lowest sample among the plurality of sample electrodes 5 is located. When the pole 5 is submerged in water, the common counter electrode 6 at a portion corresponding to the position where the sample electrode 5 is disposed also submerges in water.

このとき、図６に示されるように、試料極５の表面と共通の対極６の表面とが水Ｗを介して電気的に接続され、計測部３がケーブル２を介して試料極５と共通の対極６とを接続することで、計測部３から試料極５、水Ｗおよび共通の対極６を経由して計測部３に戻る腐食回路が形成される。
ここで、試料極５に腐食反応（アノード反応）が生じ、試料極５の表面から鉄イオンＦｅ^２＋が水Ｗに溶解して拡散すると、試料極５中に生成された電子ｅ⁻が計測部３を介して共通の対極６に供給され、共通の対極６の表面上に水Ｗを構成する水分子Ｈ_２Ｏと水中に溶存している酸素分子Ｏ_２と電子ｅ⁻が反応（カソード反応）して水酸化物イオンＯＨ⁻を生じる。 At this time, as shown in FIG. 6, the surface of the sample electrode 5 and the surface of the common counter electrode 6 are electrically connected via the water W, and the measuring unit 3 is connected to the sample electrode 5 via the cable 2. By connecting the counter electrode 6, the corrosion circuit returning from the measuring unit 3 to the measuring unit 3 via the sample electrode 5, the water W, and the common counter electrode 6 is formed.
Here, when a corrosion reaction (anode reaction) occurs in the sample electrode 5 and iron ions Fe ²⁺ are dissolved and diffused in the water W from the surface of the sample electrode 5, electrons e ⁻ generated in the sample electrode 5 are measured. The water molecule H ₂ O, which is supplied to the common counter electrode 6 via the third electrode 3 and constitutes the water W on the surface of the common counter electrode 6, reacts with oxygen molecules O ₂ dissolved in the water and electrons e ⁻ (cathode reaction). ) To form hydroxide ions OH ⁻ .

このように、アノード反応とカソード反応が試料極５と共通の対極６においてそれぞれ生じることで、共通の対極６から計測部３を通って試料極５へ腐食電流Ｉｃが流れる。この腐食電流Ｉｃは、アノード反応とカソード反応の反応速度に依存したもの、すなわち、これらの反応に関与した鉄原子Ｆｅおよび酸素分子Ｏ_２等の成分の量に依存したものとなる。 In this way, the anodic reaction and the cathodic reaction occur at the sample electrode 5 and the common counter electrode 6, respectively, so that the corrosion current Ic flows from the common counter electrode 6 to the sample electrode 5 through the measuring unit 3. The corrosion current Ic are those that depend on the reaction rate of the anodic reaction and the cathodic reaction, i.e., becomes dependent on the amount of components such as iron atoms Fe and molecular oxygen O ₂ involved in these reactions.

同様にして、計測部３により複数の試料極５を順次共通の対極６に接続することで形成される複数の腐食回路を流れる腐食電流Ｉｃがそれぞれ測定される。
水中に没したり、湿度の高い位置に配置されている試料極５においては、アノード反応およびカソード反応の速度が速くなり、大きな腐食電流Ｉｃが流れる。一方、水中に没することがなく、また、乾燥した高い位置に配置されている試料極５においては、アノード反応およびカソード反応の速度が遅くなり、腐食電流Ｉｃは小さくなる。
このように、複数の試料極５には、それぞれ、配置位置の腐食環境性に応じた腐食電流Ｉｃが流れ、この腐食電流Ｉｃが計測部３により測定される。 Similarly, the corrosion current Ic flowing through the plurality of corrosion circuits formed by sequentially connecting the plurality of sample electrodes 5 to the common counter electrode 6 is measured by the measurement unit 3.
In the sample electrode 5 immersed in water or placed in a position with high humidity, the speed of the anodic reaction and the cathodic reaction increases, and a large corrosion current Ic flows. On the other hand, in the sample electrode 5 which is not immersed in water and is disposed at a high position where it is dry, the speeds of the anodic reaction and the cathodic reaction are reduced, and the corrosion current Ic is reduced.
As described above, the corrosion current Ic according to the corrosive environment of the arrangement position flows through each of the plurality of sample electrodes 5, and the corrosion current Ic is measured by the measurement unit 3.

ここで、上述したように、複数の試料極５と共通の対極６は、互いに同一組成の材料から形成されており、電位差に起因した反応の加速が生じないように構成されている。
それぞれの試料極５に対応して測定された腐食電流Ｉｃは、生成された電子の量に対応する。そこで、腐食電流Ｉｃから電子量を求め、腐食の反応式
Ｆｅ→Ｆｅ^２＋＋２ｅ⁻
に入力することで、消費したＦｅのモル数すなわち重量を演算することができる。さらに、消費したＦｅの重量を時間で割れば、腐食速度を得ることができる。 Here, as described above, the plurality of sample electrodes 5 and the common counter electrode 6 are formed of materials having the same composition with each other, and are configured so that the reaction is not accelerated due to the potential difference.
The corrosion current Ic measured for each sample electrode 5 corresponds to the amount of generated electrons. Then, the amount of electrons is calculated from the corrosion current Ic, and the corrosion reaction formula Fe → Fe 2 ⁺⁺ 2e ⁻
, The number of moles of consumed Fe, that is, the weight can be calculated. Further, the corrosion rate can be obtained by dividing the weight of consumed Fe by time.

このようにして、計測部３により、複数の試料極５のそれぞれにおける腐食速度が算出され、所定の方向Ｄにおける腐食速度の分布が計測される。
複数の試料極５は、それぞれ、構造物１１を構成する材料と同一組成の材料から形成されているため、それぞれの試料極５に対して算出される腐食速度は、その試料極５が配置された部位の構造物１１の腐食速度とみなすことができる。
従って、構造物１１における腐食速度の分布が得られ、構造物１１の所定の方向Ｄにおける腐食環境の変化を定量的に評価することが可能となる。 In this way, the measuring unit 3 calculates the corrosion rate in each of the plurality of sample electrodes 5 and measures the distribution of the corrosion rate in the predetermined direction D.
Since each of the plurality of sample electrodes 5 is formed of a material having the same composition as the material constituting the structure 11, the corrosion rate calculated for each sample electrode 5 is determined by the value at which the sample electrode 5 is disposed. It can be considered as the corrosion rate of the structure 11 at the site where the corrosion occurred.
Therefore, the distribution of the corrosion rate in the structure 11 is obtained, and the change in the corrosion environment in the predetermined direction D of the structure 11 can be quantitatively evaluated.

一般に、腐食速度は、対象物の温度により大きく変化することが知られている。しかし、基板４の裏面４Ｂが熱伝導シート１２を介して構造物１１の表面上に貼り付けられているため、複数の試料極５および共通の対極６と構造物１１の間に大きな温度差が発生することが抑制され、腐食速度を高精度に得ることができる。 In general, it is known that the corrosion rate greatly changes depending on the temperature of an object. However, since the back surface 4B of the substrate 4 is stuck on the surface of the structure 11 via the heat conductive sheet 12, a large temperature difference occurs between the structure 11 and the plurality of sample electrodes 5 and the common counter electrode 6. Occurrence is suppressed, and the corrosion rate can be obtained with high accuracy.

計測部３は、例えば、降雨時における腐食速度、１週間または１ケ月の腐食速度の平均等、種々の条件での腐食速度の分布を得ることができ、それらを比較・評価することにより、構造物１１の腐食寿命の評価、メンテナンス計画の策定等に活用することが可能となる。 The measuring unit 3 can obtain the distribution of the corrosion rate under various conditions, such as the corrosion rate during rainfall, the average of the corrosion rate for one week or one month, and compare and evaluate the distributions. It can be used for evaluating the corrosion life of the object 11 and formulating a maintenance plan.

なお、上記の実施の形態においては、複数の試料極５と共通の対極６とが互いに同一組成の材料から形成されていたが、計測部３で算出される腐食速度の値に影響を与えない程度の電位差を、複数の試料極５と共通の対極６との間に形成することもできる。このようにすれば、共通の対極６が単独で腐食する、試料極５と共通の対極６とでアノード反応とカソード反応が逆転する、等のおそれを回避することができる。
この場合、試料極５に対して共通の対極６を貴な材料で構成することが好ましい。具体的には、共通の対極６は、複数の試料極５と同一の材料を主成分とし且つ複数の試料極５より貴である材料から形成することができる。 In the above embodiment, the plurality of sample electrodes 5 and the common counter electrode 6 are formed of materials having the same composition with each other, but do not affect the value of the corrosion rate calculated by the measuring unit 3. A degree of potential difference can be formed between the plurality of sample electrodes 5 and the common counter electrode 6. In this way, it is possible to avoid the possibility that the common counter electrode 6 is corroded by itself and that the anode reaction and the cathode reaction are reversed between the sample electrode 5 and the common counter electrode 6.
In this case, the common counter electrode 6 for the sample electrode 5 is preferably made of a noble material. Specifically, the common counter electrode 6 can be formed from a material that has the same material as the plurality of sample electrodes 5 as a main component and is nobler than the plurality of sample electrodes 5.

例えば、鉄にクロムまたはニッケルを添加した合金鋼は、クロムまたはニッケルの添加量を増加するほど自然電位が貴になるため、構造物１１が溶接構造用圧延鋼材からなる場合に、複数の試料極５を鉄めっきから形成すると共に、共通の対極６をクロムまたはニッケルが添加された合金鋼から形成することで、試料極５に対して共通の対極６を貴な材料とすることができる。 For example, in the case of alloy steel in which chromium or nickel is added to iron, the spontaneous potential becomes higher as the amount of chromium or nickel added increases. Therefore, when the structure 11 is made of a rolled steel material for a welding structure, a plurality of sample electrodes By forming the counter electrode 6 from iron plating and forming the common counter electrode 6 from an alloy steel to which chromium or nickel is added, the common counter electrode 6 with respect to the sample electrode 5 can be made of a noble material.

日本工業規格（ＪＩＳ）には、機械構造用合金鋼として、クロムモリブデン鋼（ＳＣＭ）のクロムの最大添加量は１．５％、ニッケルクロムモリブデン鋼（ＳＮＣＭ）のクロムの最大添加量は３．５％、ニッケルの最大添加量も３．５％と記載されている。そこで、最大添加量３．５％の範囲内でクロムまたはニッケルが添加された合金鋼あるいは最大添加量３．５％の範囲内でクロムが添加されると共に最大添加量３．５％の範囲内でニッケルが添加された合金鋼を用いて共通の対極６を形成すれば、計測部３で算出される腐食速度の値に影響を与えない程度の電位差を、複数の試料極５と共通の対極６との間に形成することが可能になる。 According to Japanese Industrial Standards (JIS), the maximum amount of chromium added to chromium molybdenum steel (SCM) is 1.5%, and the maximum amount of chromium added to nickel chromium molybdenum steel (SNCM) is 3. 5%, and the maximum addition amount of nickel is also described as 3.5%. Therefore, alloy steel to which chromium or nickel is added within the maximum addition amount of 3.5% or chromium is added within the maximum addition amount of 3.5% and the maximum addition amount is within the range of 3.5%. When the common counter electrode 6 is formed by using an alloy steel to which nickel is added, a potential difference that does not affect the value of the corrosion rate calculated by the measuring unit 3 is set to a common counter electrode with the plurality of sample electrodes 5. 6 can be formed.

なお、基板４が、ガラスエポキシ樹脂等の絶縁性樹脂から形成されているが、これに限るものではなく、例えば金属材料からなる基板を用いることもできる。ただし、この場合には、電気的短絡を防止するため、基板の表面上に絶縁層を形成し、絶縁層の上に複数の試料極５、共通の対極６、複数の第１の端子７、第２の端子９、配線８および１０を形成する必要がある。
基板を構成する金属材料は、錆などの腐食生成物が基板の表面に堆積しにくい材料、例えばステンレス鋼等を用いるのが好ましい。 Although the substrate 4 is formed from an insulating resin such as a glass epoxy resin, the present invention is not limited to this. For example, a substrate made of a metal material can be used. However, in this case, in order to prevent an electrical short circuit, an insulating layer is formed on the surface of the substrate, and a plurality of sample electrodes 5, a common counter electrode 6, a plurality of first terminals 7, It is necessary to form the second terminal 9 and the wirings 8 and 10.
As the metal material constituting the substrate, it is preferable to use a material in which corrosion products such as rust do not easily deposit on the surface of the substrate, for example, stainless steel or the like.

実施例１
ガラスエポキシ樹脂からなる長さ１６０ｍｍ、幅７０ｍｍの基板４を使用し、図２に示されるように、基板４の長さ方向を所定の方向Ｄとして、基板４の表面４Ａ上に３２個の試料極５を配列形成すると共に、所定の方向Ｄにおける試料極５の配置位置をすべて含むように所定の方向Ｄに延びる共通の対極６を形成した。３２個の試料極５は、それぞれ、所定の方向Ｄにおける幅１ｍｍ、互いに隣接する試料極５の間隔を１ｍｍとして、所定の方向Ｄに沿って６３ｍｍの長さにわたっている。さらに、基板４の表面４Ａ上に３２個の第１の端子７、１個の第２の端子９、３２本の配線８および１本の配線１０を配置して電極部１を形成し、３２本のケーブル２を介して計測部３に３２個の第１の端子７を接続すると共に１本のケーブル２を介して計測部３に第２の端子９を接続することにより、図１に示される腐食センサを形成した。 Example 1
As shown in FIG. 2, using a substrate 4 made of glass epoxy resin and having a length of 160 mm and a width of 70 mm, the length direction of the substrate 4 is defined as a predetermined direction D, and 32 samples are formed on the surface 4A of the substrate 4. The poles 5 were arranged and formed, and a common counter electrode 6 extending in the predetermined direction D was formed so as to include all the arrangement positions of the sample electrodes 5 in the predetermined direction D. Each of the 32 sample electrodes 5 has a width of 1 mm in the predetermined direction D and a distance of 1 mm between the sample electrodes 5 adjacent to each other, and extends over a length of 63 mm along the predetermined direction D. Further, 32 first terminals 7, 1 second terminal 9, 32 wirings 8 and 1 wiring 10 are arranged on the surface 4 </ b> A of the substrate 4 to form the electrode section 1, and 32. By connecting the 32 first terminals 7 to the measuring unit 3 via the two cables 2 and connecting the second terminals 9 to the measuring unit 3 via the single cable 2 as shown in FIG. Formed corrosion sensor.

鋼材（ＳＭ４９０Ａ）の表面上に熱伝導シートを介して腐食センサの電極部１を貼り付け、所定の方向Ｄを鉛直方向に向けて、０．１ｗｔ％ＮａＣｌ水溶液を含ませた砂からなる土壌中に鋼材を差し込んで腐食の実験を行った。なお、電極部１の３２個の試料極５の一部が土壌の表面から大気中に露出し、残部が土壌中に位置するように、鋼材を差し込んだ。
鋼材を土壌中に差し込まれた状態に保持し、約６か月後に取り出した。取り出した鋼材に対して脱スケールを行い、所定の方向Ｄすなわち鉛直方向のそれぞれの高さにおいて実測された平均腐食深さを図７に曲線Ｃ１で示す。また、腐食センサの計測部３で計測された複数の試料極５における腐食速度から推定されるそれぞれの高さの腐食深さを図７に棒グラフで示す。 The electrode portion 1 of the corrosion sensor is attached to the surface of a steel material (SM490A) via a heat conductive sheet, and a predetermined direction D is oriented vertically so that the electrode portion 1 is made of sand containing a 0.1 wt% NaCl aqueous solution. A corrosion test was conducted by inserting steel into the steel. The steel material was inserted so that a part of the 32 sample electrodes 5 of the electrode part 1 was exposed to the atmosphere from the surface of the soil, and the rest was located in the soil.
The steel was kept inserted in the soil and removed after about 6 months. The taken-out steel material is subjected to descaling, and the average corrosion depth actually measured in the predetermined direction D, that is, at each height in the vertical direction, is shown by a curve C1 in FIG. FIG. 7 is a bar graph showing the respective corrosion depths estimated from the corrosion rates of the plurality of sample electrodes 5 measured by the measurement unit 3 of the corrosion sensor.

腐食センサの出力から推定された腐食深さは、実測された平均腐食深さと比較して、所定の方向Ｄに沿った全体のプロファイルが類似する傾向を示しており、腐食センサを用いることで、鋼材の所定の方向Ｄにおける腐食環境の変化を定量的に評価し得ることが確認された。 Corrosion depth estimated from the output of the corrosion sensor, the overall profile along the predetermined direction D shows a tendency to be similar to the average measured corrosion depth, and by using the corrosion sensor, It was confirmed that the change of the corrosion environment in the predetermined direction D of the steel material could be quantitatively evaluated.

実施例２
２６．４ｗｔ％ＮａＣｌ水溶液を含ませた砂からなる土壌中に鋼材を差し込んだ他は、実施例１と同様にして鋼材の腐食の実験を行った。
土壌中に差し込んでから約６か月後に取り出した鋼材に対して脱スケールを行い、所定の方向Ｄのそれぞれの高さにおいて実測された平均腐食深さを図８に曲線Ｃ２で示す。また、腐食センサの計測部３で計測された複数の試料極５における腐食速度から推定されるそれぞれの高さの腐食深さを図８に棒グラフで示す。 Example 2
An experiment on corrosion of steel was performed in the same manner as in Example 1 except that the steel was inserted into sand made of a 26.4 wt% NaCl aqueous solution.
The steel material taken out about six months after being inserted into the soil is descaled, and the average corrosion depth actually measured at each height in the predetermined direction D is shown by a curve C2 in FIG. FIG. 8 is a bar graph showing the respective corrosion depths estimated from the corrosion rates of the plurality of sample electrodes 5 measured by the measurement unit 3 of the corrosion sensor.

実施例１の実験結果と同様に、腐食センサの出力から推定された腐食深さは、実測された平均腐食深さと比較して、所定の方向Ｄに沿った全体のプロファイルが類似する傾向を示し、腐食センサを用いることで、鋼材の所定の方向Ｄにおける腐食環境の変化を定量的に評価し得ることが確認された。 Similarly to the experimental result of Example 1, the corrosion depth estimated from the output of the corrosion sensor shows a tendency that the entire profile along the predetermined direction D is similar to the actually measured average corrosion depth. By using the corrosion sensor, it was confirmed that the change of the corrosion environment of the steel material in the predetermined direction D can be quantitatively evaluated.

１電極部、２ケーブル、３計測部、４基板、４Ａ表面、５試料極、６共通の対極、７第１の端子、８，１０配線、９第２の端子、１０絶縁部、１１熱伝導シート、１２構造物、Ｄ所定の方向、Ｗ水、Ｉｃ腐食電流。 1 electrode part, 2 cable, 3 measuring part, 4 substrate, 4A surface, 5 sample electrode, 6 common counter electrode, 7 first terminal, 8, 10 wiring, 9 second terminal, 10 insulating part, 11 heat conduction Sheet, 12 structures, D predetermined direction, W water, Ic corrosion current.

Claims

A plate-shaped substrate arranged on the front surface of a structure to be measured and having a front surface and a back surface ,
A plurality of sample poles are and arranged in a predetermined direction on said surface of said substrate,
A common counter electrode extending in the predetermined direction aligned with the plurality of sample electrode such that the disposed on the surface and including the arrangement position of the plurality of sample electrode in the predetermined direction of the substrate,
The predetermined direction based on a plurality of corrosion currents flowing through a plurality of corrosion circuits connected to the plurality of sample electrodes and the common counter electrode and formed by connecting the plurality of sample electrodes to the common counter electrode, respectively. and a measuring unit for measuring the distribution of the corrosion rate in,
The corrosion sensor, wherein the plurality of sample electrodes and the common counter electrode are arranged on the same surface on the surface of the substrate .

The corrosion sensor according to claim 1, wherein the common counter electrode is made of the same material as the plurality of sample electrodes.

The corrosion sensor according to claim 2, wherein the plurality of sample electrodes and the common counter electrode are formed by iron plating.

2. The corrosion sensor according to claim 1, wherein the common counter electrode is mainly composed of the same material as the plurality of sample electrodes and is made of a material which is more noble than the plurality of sample electrodes. 3.

The corrosion sensor according to any one of claims 1 to 4, wherein the back surface of the substrate is attached to a surface of the structure via a heat conductive sheet.

The measuring unit integrates, for each of the plurality of sample electrodes, a corrosion current flowing through a corrosion circuit formed by connecting the sample electrode to the common counter electrode, so that a corrosion rate at the sample electrode is obtained. The corrosion sensor according to any one of claims 1 to 5, which measures the following.